Currently, cheese manufactures use plywood, metal and a small number of plastic re-usable containers to ship cheese. Each of these containers suffers a variety of shortcomings, as described below.
The predominant container in the industry for shipping bulk cheese is a plywood box with metal frame components. Typically, a set of plywood walls, including top and bottom sections, are connected together to form a square or rectangular box. Because the cheese can assert significant pressure on the walls, metal bands on the outside of the walls are used to prevent or reduce bowing of the walls. Because this container is made of wood, which is porous, and steel, which can rust, the surfaces must be resealed for hygienic reasons. This is done by coating the wood components with wax and stripping the paint from the metal components and repainting. When the cheese reaches its destination, the cheese box is broken down and shipped back to the cheese manufacturer for reuse. However, the wax must be stripped and re-applied before the returnable container is reused. This is a time intensive process that is often performed at third party facilities. Additionally, popular versions of this wood/metal container weigh approximately 118 lbs. and are difficult to assemble. The weight of the container does not allow a full truckload of cheese to be shipped because gross trailer weights are exceeded prior to the truck being full.
Metal containers made from stainless steel are sometimes used in the industry, but are restricted to in-plant use. This usage limitation is because the container is extremely expensive, heavy, dents easily and does not collapse for return shipment to point of origin.
Plastic containers manufactured using the low pressure structural foam process and molded from polycarbonate material represent approximately 1% of the market (circa 2005). One example of such as container is described in U.S. Pat. No. 5,287,981 to Wheeler. The known issues with commercial implementations of this cheese box are: (i) liquid whey gets trapped in the ribs of the lid and sidewalls; (ii) the container is susceptible to stress cracking because of the foam molding process; (iii) the finished surface of a structural foam part is not easily cleaned because it is not sufficiently smooth; and (iv) a 4 ft. long pry bar is typically required to open the container to access the cheese or a capital intensive automated opener can be used, requiring utilizing a fork truck to put the container in the device. As a subsidiary problem, if stress cracks do form in the plastic when cheese is in the box, cheese can enter the cracks. When the cheese is removed from the box, the cracks can reseal, trapping some residual amount of cheese. The cheese trapped in the sealed cracks can be difficult to remove, making reuse of the cheese box unhygienic. Furthermore, the use of a large pry bar to open the containers often causes damage to the containers.
As another deficiency of existing containers is that they make use of 6 to 8 steel coil springs that keep the cheese compressed during storage and transport. The springs are difficult to separate from one another when shipped back to point of origin and re-coated with wax.